fixing some tests

tests/_pages/RegistrationPage.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace tests\_pages;
+
+use yii\codeception\BasePage;
+
+/**
+ * Represents registration page.
+ *
+ * @property \FunctionalTester $actor
+ */
+class RegistrationPage extends BasePage
+{
+    /** @inheritdoc */
+    public $route = '/user/registration/register';
+
+    /**
+     * @param $username
+     * @param $email
+     * @param $password
+     */
+    public function register($email, $username = null, $password = null)
+    {
+        $this->actor->fillField('#register-form-email', $email);
+        $this->actor->fillField('#register-form-username', $username);
+        if ($password !== null) {
+            $this->actor->fillField('#register-form-password', $password);
+        }
+        $this->actor->click('Sign up');
+    }
+}